The color image is a composite of three pictures taken by the Viking Orbiter 2 from an altitude of 24,370 kilometers (15,143 miles) on its 191st revolution of Mars. The three black-and-white pictures which make up the color composite represent red, green and violet filtered exposures. One lobe of the south polar cap is seen at left center. The two prominent craters at upper left are Rayleigh (left) and Burroughs. Burroughs crater is approximately 105 kilometers (65 miles) in diameter. The dark patches on the floors of the larger craters are believed to be sand dunes, although most of the other large and small craters in the picture do not appear to contain such deposits. The three, bright white patches at left center appear to be frost deposits on the summits of mountains. The wispy, white diagonal streaks in the crater at the far left are clouds, and the violet patches reflect compositional differences in the surface soils.
